Machines for orienting and aligning articles such as empty plastic bottles or containers are known, which machines comprise a plurality of orientation cavities associated to a rotary structure and distributed along a perimetric ring thereof, such that said orientation cavities rotate with the rotary structure in a closed circuit. The orientation cavities are provided with an upper inlet for receiving articles and with an open bottom for the passage of the articles. The rotary structure has a plurality of funnel-shaped alignment conduits, each of which is arranged below a respective orientation cavity to receive an article falling therefrom. The machines of this type include support means for temporarily supporting the articles in said orientation cavities and for dropping them into the corresponding alignment conduits in one or more predetermined sites of said closed circuit. In each of the orientation cavities there are arranged support and/or stop elements configured to cooperate with parts of the article when the latter falls through the open bottom of the orientation cavity to confer a predetermined orientation, for example, standing on its base, to the article inside the alignment conduit. The articles are generally accumulated in a disorderly manner in a space inside the perimetric ring of the rotary structure and means are provided for loading the articles from said space to the orientation cavities.
Patent FR-A-1390960 (Hoffco) discloses a machine for orienting and aligning articles of the type described above, in which the space inside the perimetric ring of the rotary structure where the orientation cavities are located and the alignment conduits define a container for the disordered articles, having a cylindrical wall rotating with a rotating structure and a stationary convex conical bottom to propel the disordered articles towards the cylindrical walls. The mentioned convex conical bottom is at a lower level than the orientation cavities. Adjacent to the rotating cylindrical wall there is a stationary helical ramp cooperating with vertical ribs projecting from the rotating cylindrical wall to raise the articles from the bottom of the container to the orientation cavities. A number of positioning machines based on the operating principle described in the mentioned patent FR-A-1390960 have subsequently appeared. However, the implementation of the rotating cylindrical wall and the stationary bottom and ramp involves a relatively complex construction that negatively affects the manufacturing cost and productive performance of the machine.